The use of inflatable devices has long been associated with water sports and recreational activities involving water. For the most part, this has been the case because inflatable devices are generally capable of floating on water. With the explosion of the availability of inexpensive plastic products, recreational devices such as beach balls and water wings became increasingly common at pools and beaches during the latter half of the 20th century.
Inflatable devices have also been used for more sophisticated recreational purposes. For example, inner tubes have traditionally been used as a simple watercraft. Inner tubes float in water, even with a rider in place, and provide a relatively ergonomic shape to secure the rider comfortably. They are also sufficiently durable for this use. Inner tubes can be used to float in a calm body of water, or they can be used as passive vehicles in a flowing body of water, such as a river. Inner tubes can also be towed behind powered watercraft. These activities are known as “tubing.”
Inner tubes are well suited for water recreation, especially given that they were not designed for this use. However, they have several drawbacks, which in part result from being used outside of their design specifications. One major drawback is that they are designed to be inflated at a high pressure. This means that a high pressure pump must be used to inflate them. This also means that it takes a relatively long time to inflate and deflate inner tubes. There is also a risk of violent rupture because of the high potential energy of a high pressure reservoir. Such an event could cause human injury or property damage.
As a result, there has been a move to produce simple watercraft and other water recreation devices from PVC instead of rubber, as in an inner tube. Watercraft and devices in this newer wave tend to be low pressure inflatables. They also incorporate design improvements in ergonomics and maneuverability for recreational use.
Despite being inflated to a low pressure, these devices often have a substantial volume of inflatable space. This makes fast and easy inflation and deflation an engineering challenge. Most of the design work that goes in to addressing this challenge is focused on the air valves for these devices. The valves must be able to accommodate a large flow volume for both inflation and deflation. They must be air tight when closed, even during hard use or stressful conditions. Furthermore, they must accommodate inflation from sources not capable of producing high inflation pressures. Thus, there remains a need in the art for air valves for inflatable devices that meet these design requirements.